Cars are, as usual, a really poor analogy. It's true I have absolutely no idea how to fix a car if it breaks down; however, fixing cars is a highly specialized skill (especially these days) and requires expensive equipment. Companies like Facebook, meanwhile, spend millions of dollars on usability testing so that their websites and applications are easy to use, and there is the expectation that anybody _can_ use them. Now if we were talking about programming, or even system administration, it would be a more apt analogy.